[A case of permanent pacemaker implantation in small infant using steroid-eluting epicardial pacing lead: changes of the pacing threshold in acute phase]

A 1-year-old infant with complete atrioventricular block was successfully treated with the pacemaker implantation using steroid-eluting epicardial pacing lead by the subxyphoid approach. Pacing threshold after implantation were measured frequently to use the function named "Capture management" of the generator (Medtronic: Kappa, Model 701). The postoperative pacing threshold were kept lower and stabilized after 5 weeks.

Soluble Fas (APO-1/CD95) isoform in adult T-cell leukemia

Fas (APO-1/CD95) consists mainly of 2 isoforms, membrane-anchored (mFas) and soluble (sFas), both of which can mediate apoptosis through the Fas-signalling process, not only in normal but also in leukemia T-cells. This suggests that aberrant expression of either mFas or sFas may affect the natural history of T-cell neoplasms, such as adult T-cell leukemia (ATL). For studying the tumor biology related to Fas-mediated apoptosis, ATL cells with up-regulated Fas proteins and its mRNAs are convenient and useful for understanding apoptotic oncology as it occurs in nature. Most attention, so far, has been focused on mFas, and little is known about neoplasms from the viewpoint of sFas. Accordingly, we herein review and discuss the biological and clinical implications of sFas in ATL.

Breast cancer resistance protein directly confers SN-38 resistance of lung cancer cells

Breast cancer resistance protein (BCRP), an ABC half-transporter, is overexpressed in cancer cell lines selected with doxorubicin/verapamil, topotecan, or mitoxantrone. BCRP-overexpressing cells show cross-resistance to camptothecin derivatives such as irinotecan, SN-38 (the active metabolite of irinotecan), and topotecan. To test whether BCRP confers SN-38 resistance, we selected two SN-38 resistant sublines from PC-6 human small-cell lung cancer cells by SN-38, and then characterized these cells. Compared to PC-6 cells, the resistant sublines PC-6/SN2-5 and PC-6/SN2-5H were approximately 18- and 34-fold resistant, respectively. The intracellular SN-38 accumulation was reduced in the sublines, and BCRP mRNA was overexpressed in proportion to the degree of SN-38 resistance. These findings suggest that BCRP confers SN-38 resistance in the sublines. To confirm this hypothesis, PC-6/SN2-5 cells were transfected with antisense oligonucleotides complementary to portions of BCRP mRNA. The antisense oligonucleotides significantly suppressed BCRP mRNA expression, and enhanced SN-38 sensitivity in the subline. These data indicate that BCRP is directly involved with SN-38 resistance, by efflux transport of SN-38.

Birth cohort effects on incidence of lung cancers: a population-based study in Nagasaki, Japan

Smoking prevalence remains high (around 60%) among Japanese males, but smoking initiation among males born in the 1930s decreased by approximately 10% due to economic difficulties following World War II. The present study was designed to examine whether this temporary decline in smoking initiation influenced the subsequent incidence of lung cancers, especially adenocarcinoma. Trends of lung cancer incidence by histological type in both sexes were investigated using data from the population-based cancer registry in Nagasaki, Japan, from 1986 through 1995. During this period, 5668 males and 2309 females were diagnosed as having lung cancer, and the overall incidence of lung cancers among both sexes remained stable. However, males aged 55 - 59 years showed a decrease in the age-specific incidence of adenocarcinoma and squamous-cell carcinoma (P < 0.05 and P < 0.01, respectively). In birth cohort analyses, the incidence of adenocarcinoma and squamous-cell carcinoma was lower in the 1935 - 1939 birth male cohort than in the successive cohorts. The incidence of lung cancers among females with low smoking prevalence did not change with birth cohort. The low smoking initiation among the 1935 - 1939 birth male cohort appeared to have resulted in a decreased incidence of adenocarcinoma and squamous cell carcinoma among middle-aged Japanese males. The present study suggests that smoking prevention has an effect in reducing the incidence of lung adenocarcinoma, as well as squamous-cell carcinoma, among smokers.

Clinical and oncological significance of aberrant Fas (APO-1/CD95) isoform expression in adult T-cell leukemia

Fas (APO-1/CD95), a transmembrane death receptor mediating apoptosis, can induce cell deathin vivo andin vitro of not only normal T-cells but also leukemic T-cells. This indicates that dysfunction in T-cell apoptosis may influence the natural history of the T-cell neoplasms, such as adult T-cell leukemia (ATL) caused by the retrovirus HTLV-1. Fas is ubiquitous, and down-regulated or mutated Fas has been widely detected in tumor cells that escape from elimination via Fas-mediated apoptosis. De novo fresh ATL cells and cell lines derived from the de novo cells, however, express Fas abundantly on the cell surface and are susceptible to Fas ligand and agonistic agents. On the other hand, there are two types of Fas gene transcripts, full-length and alternatively splicing truncated forms corresponding to membrane and soluble Fas isoforms, respectively. Focusing on membrane and soluble Fas isoforms and ATL pathology mediated by apoptosis, this paper reviews and discusses our ATL cases and ATL cell lines, which provide useful "experiments of nature" for understanding the role of Fas-mediated apoptosis in tumor biology.

Real-time polymerase chain reaction for quantification of HTLV-1 proviral load: application for analyzing aberrant integration of the proviral DNA in adult T-cell leukemia

We describe the establishment of a real-time polymerase chain reaction (PCR) assay for the quantitative estimation of human T-cell leukemia virus type 1 (HTLV-1) proviral load using a LightCycler Technology (Roche Diagnostics, Mannheim, Germany) instrument. Proviral DNA level represents a measure of the integrated viral genome in host cells, so we applied this technique to evaluate the tumor burden in adult T-cell leukemia (ATL) patients with aberrant integration patterns of HTLV-1 detected by standard Southern blot hybridization (SBH) analysis. In 14 of our 15 ATL cases with 2 or more bands detected by SBH analysis, the ATL cells were shown to harbor multiple copies of the provirus within 1 ATL cell. This result suggests the usefulness of real-time PCR quantification for the study of the relationship between ATL pathology and HTLV-1-induced pathogenesis.

[Activities of antimicrobial agents against 5,180 clinical isolates obtained from 26 medical institutions during 1998 in Japan. Levofloxacin--Surveillance Group]

The surveillance study was conducted to determine the antimicrobial activity of fluoroquinolones (ofloxacin, levofloxacin, ciprofloxacin, tosufloxacin) and other 20 antimicrobial agents against 5,180 clinical isolates obtained from 26 medical institutions during 1998 in Japan. The resistance to fluoroquinolones was remarkable in Enterococci, methicillin-resistant staphylococci and Pseudomonas aeruginosa from UTI. However, many of the common pathogens such as Streptococcus pneumoniae including penicillin-resistant isolates, methicillin-susceptible Stahylococcus aureus, Moraxella catarrhalis, the family of Enterobacteriaceae, Haemophilus influenzae including ampicillin-resistant isolates have been kept to be susceptible to fluoroquinolones. About 90% of P. aeruginosa isolates from RTI were susceptible to fluoroquinolones. In conclusion, the results from this surveillance study suggest that fluoroquinolones are useful in the treatment of various bacterial infections including respiratory infections.

[Characteristics of plasma DNA and its application for detection of K-ras gene mutation]

DNA diagnosis is useful and significant for clinical oncology, but its use is limited due to a difficulty in preparing tumor-derived DNA materials. To overcome this problem, we investigated the characterization of plasma DNA and it application to successfully detecting K-ras mutation at codon 12 in normal persons, hematopoietic neoplasms, and solid tumors. The range of plasma DNA in each group was 15.8 +/- 5.2 ng/ml, 43.3 +/- 29.8 ng/ml, and 26.8 +/- 17.0 ng/ml, respectively. The ranges in patients with solid tumor were gradually decreased to the normal level of around 15 ng/ml in 3 weeks postoperatively. Plasma DNAs consisted of about 200 bp DNA fragmentation and were convenient for PCR amplification of K-ras gene. The mutation at codon 12 by PCR-RFLP analysis was detected in 13(27%) of 49 patients with solid tumors such as pancreatic cancer, breast cancer, colon cancer, and gastric cancer. The diagnostic specificity was 100%. Serial observations by the PCR-RFLP analysis revealed disappearance of the mutant K-ras about 7 days after successful curative surgery in a patient with gastric cancer.

Correlation of urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG), a biomarker of oxidative DNA damage, and clinical features of hematological disorders: a pilot study

The 8-hydroxy-2'-deoxyguanosine (8-OHdG), presently the most popular marker for oxidative DNA damage, level has been reported to be elevated in patients with various malignancies. In the present study, urinary 8-OHdG was examined in 44 patients with hematological disorders (13 malignant lymphoma, 11 adult T cell leukemia/lymphoma (ATL), 10 acute leukemia, and 10 myelodysplastic syndrome (MDS)) by an enzyme-linked immunosorbent assay. The pre-therapy level of urinary 8-OHdG in ATL patients was significantly elevated compared with normal controls (25.3+/-12.9 vs. 11.9+/-7.3 ng/mg, P<0.05). Although patients with lymphoma, acute leukemia and MDS also showed higher urinary 8-OHdG levels than normal controls, the differences were not significant. However, two patients with refractory anemia with excess blasts in transformation (RAEB-t) having extreme monocytosis and neutrophilia showed exceptionally high urinary 8-OHdG levels (161.0 and 218.9 ng/mg). Urinary 8-OHdG excretion increased transiently with chemotherapy, and this fluctuation was significant irrespective of the disorder (P<0.05). Interestingly, lymphoma patients with high LDH, advanced stage, poor performance status or International Prognostic Index (IPI) of high/high-intermediate risk had significantly elevated urinary 8-OHdG levels (P<0.05-<0.001). These latter results suggest that urinary 8-OHdG may be a reliable prognostic marker in lymphoma patients and should encourage large scale and long term follow up studies.

Qualitative and quantitative characterization of Fas (CD95) expression and its role in primary human acute leukemia cells

Fas antigen, a cell surface molecule, directly mediates apoptosis, and is expressed on a limited number of human tissues. Blood or bone marrow samples from patients with acute myelogenous leukemia (AML), acute lymphoblastic leukemia (ALL) and mixed leukemia were examined qualitatively and quantitatively for the expression of Fas as well as its function using flow cytometry and the annexin V staining method. Fas expression was flow cytometrically unimodal with heterogeneous density, and showed quantitatively characteristic features in different diseases: undetectable in mixed leukemia, faint to weak in ALL, low in M0 and M1, and variable (low to strong) in M2, M3, M4, and M5. Both the full-length and the alternatively spliced truncated mRNAs were detected constitutively even in acute leukemia cells with qualitatively negative and quantitatively faint Fas, and the band density of the former transcripts detected by RT-PCR was correlated with the level of expression of the Fas protein. Short-term culturing of freshly isolated leukemia cells gave rise to an increase of Fas density. In acute leukemia cells, the apoptosis induced by anti-Fas MoAb was compared with that induced by etoposide (a topoisomerase II inhibitor). We found that fresh ALL and AML cells were resistant to the anti-Fas IgM antibody, while etoposide could trigger apoptosis in all types of leukemia tested. The combined effects of the anti-Fas MoAb and etoposide were not always synergistic. These results suggest that Fas is a biological marker for characterizing ALL and AML cells, and provide insight into creating a new therapeutic modality using cytotoxic drugs and cytokines together with modulation of Fas.

In vitro activity of telithromycin (HMR3647), a new ketolide, against clinical isolates of Mycoplasma pneumoniae in Japan

The in vitro activity of telithromycin (HMR3647), a new ketolide, against Mycoplasma pneumoniae was determined by the broth microdilution test using 41 clinical isolates obtained in Japan, as compared with those of five macrolides (erythromycin, clarithromycin, roxithromycin, azithromycin, and josamycin), minocycline, and levofloxacin. Telithromycin was less potent than azithromycin, but it was more active than four other macrolides, minocycline, and levofloxacin; its MICs at which 50 and 90% of the isolates tested were inhibited were both 0.00097 microg/ml, justifying clinical studies to determine its efficacy for treatment of M. pneumoniae.

Lactacystin activates FLICE (caspase 8) protease and induces apoptosis in Fas-resistant adult T-cell leukemia cell lines

Lactacystin (LC) is a specific inhibitor of the proteasome, and has recently been shown to induce apoptosis in certain cell lines. In the present study, we established Fas-resistant adult T-cell leukemia (ATL) cell subclones RSO4 and RST1 from their parental Fas-sensitive cell lines SO4 and ST1, and examined whether LC can overcome Fas resistance. LC completely inhibited proteasome function as determined by a peptidyl-MCA substrate (LLVY-MCA and LLE-MCA), and induced apoptosis in these cell lines irrespective of Fas sensitivity at low concentrations (approximately 10 microM). LC induced the activation of caspase 3 (CPP32/Yama) and caspase 6 proteases in an identical manner to Fas-mediated apoptosis. Moreover, LC induced the activation of caspase 8 (FLICE) protease, which is the initiator of the Fas-mediated apoptotic cascade. Synthesized proteasome inhibitory peptide MG-115 (ZLLnV-CHO) also induced apoptosis in these cell lines. These results indicated that proteasome inhibitors overcome Fas-resistance by bypassing the proximal part of the Fas signal. Inhibition of the proteasome function may be a new strategy for the treatment of ATL.

Expression and phosphorylation status of retinoblastoma protein in adult T-cell leukemia/lymphoma

The deletion or hyperphosphorylation of the retinoblastoma protein (pRB), is reported to progress various tumors. But its relevance to adult T-cell leukemia/lymphoma (ATL) remains to be elucidated. To better understand the role of pRB in ATL, we examined the expression and phosphorylation status of pRB in three ATL cell lines and 43 clinical samples, eight peripheral blood samples and 35 lymph node samples, from patients with ATL by Western blotting. In addition, 30 lymph node sections were also evaluated immunohistochemically. As a result, Western blotting analysis revealed that the pRB in the ATL cell lines was in the hyperphosphorylated, but that in 39 of 43 clinical samples, pRB was exclusively in the hypophosphorylated form. Four peripheral blood samples were negative for pRB. Immunohistochemistry revealed that the lymph nodes of all of 30 patients tested were positive for pRB at various staining levels, weak, mild, and strong. But weak expression may be essentially negative for pRB function. Patients with weak pRB expression in their lymph nodes lived significantly shorter lives than those with mild expression. Surprisingly, patients with strong expression also showed a significantly worse prognosis than those with mild expression. Although only the absence of pRB expression was considered previously to be indicative of RB functional loss, it has been reported recently that overexpression of pRB is correlated with progression of disease in patients with advanced bladder carcinoma or follicular lymphoma. These findings indicate that pRB controls tumor proliferation not only as a cell cycle regulator but also by other mechanisms, possibly through the inhibition of apoptosis, as suggested by recent findings in an osteosarcoma cell line, Saos-2. In conclusion, pRB may play an essential role in its hypophosphorylated form for progression of ATL, as well as a cell cycle promoter in hyperphosphorylated or negative/excessive reduced form.

Penetration of clinical isolates of Pseudomonas aeruginosa through MDCK epithelial cell monolayers

Pseudomonas aeruginosa causes both invasive (bacteremic) and chronic noninvasive infections. A simple in vitro system to screen P. aeruginosa clinical isolates for their capacity to penetrate MDCK cell monolayers has been developed. By means of this system, P. aeruginosa clinical isolates, including 32 blood and 45 respiratory isolates, were examined. When monolayers were infected with 3.5x107 cfu of bacteria, significantly more blood (93.7%) than respiratory (54.4%) isolates (P<.001) were detected in the basolateral medium after 3 h. Penetration ability was usually independent of cytotoxicity. Only 8 (4 blood and 4 respiratory) isolates were cytotoxic, possessed exoU, and passed through the monolayer after epithelial cell death, associated with a marked drop in transepithelial electrical resistance. Conversely, noncytotoxic isolates with high penetration ability but without severe epithelial damage were invasive. This system is well suited for screening clinical isolates and their mutants for specific genes conferring the invasiveness phenotype.

Minimally differentiated acute myeloid leukemia (AML-M0) with extensive erythrophagocytosis and del(20)(q11) chromosome abnormality

We describe an 84-year-old woman who presented severe pancytopenia and 36.6% of blasts accompanied with erythrophagocytosis in the bone marrow. According to cytochemical and immunological findings, a diagnosis of minimally differentiated acute myeloid leukemia (AML-M0) was established. Cytogenetic analysis revealed del(20)(q11) which were previously reported for one case each of ALL and MDS associated with cytophagocytosis by blasts, leading us to speculate a disease entity. Interestingly, a high expression of mRNA of TNF-alpha was detected by RT-PCR on the bone marrow mononuclear cells.

Discrepant expression of membrane and soluble isoforms of Fas (CD95/APO-1) in adult T-cell leukaemia: soluble Fas isoform is an independent risk factor for prognosis

The Fas signalling system probably plays a critical role in the natural and chemotherapeutic cell death machinery, suggesting that aberrant Fas expression is involved in growth control of tumours. The membrane isoform (mFas) is a 45 kD cell surface protein containing a single transmembrane region, and induces apoptosis in normal or tumour cells, whereas the soluble isoform (sFas) lacks the transmembrane domain due to alternative splicing of the transcript and is thought to block Fas-mediated apoptosis. To clarify the clinical roles of expression of these two Fas isoforms in adult T-cell leukaemia (ATL), we investigated the levels of the Fas isoforms in 81 patients with ATL. The expression patterns of the Fas isoforms were heterogenous, and there was no significant correlation between mFas and sFas levels: 10/81 cases were negative for mFas and had high serum sFas levels, whereas the remaining 71 cases were positive for mFas and had various levels of expression of the two Fas isoforms. Irrespective of the status of mFas expression in leukaemic cells, the mRNAs encoding these isoforms were always detectable, indicating the potential for protein translation. Although mFas expressed on freshly isolated ATL cells could iduce apoptosis in vitro, positive versus negative mFas status was not associated with any clinical aspects of ATL, whereas the sFas level was strongly correlated with clinical parameters such as serum LDH activity, tumour burden, serum soluble IL-2R level, hypercalcaemia and prognosis. These results suggest that the ratio of Fas isoforms varies, and high expression of the sFas protein and message reflects the malignant behaviour of ATL and is an independent risk factor for the prognosis.

Fas-resistance in ATL cell lines not associated with HTLV-I or FAP-1 production

A preventive role for human T-cell leukemia virus type-I (HTLV-I) and Fas-associated phosphatase-1 (FAP-1) in Fas-mediated apoptosis has been reported in HTLV-I-infected cells. In the present study, we examined whether these molecules increased during the acquisition of Fas-resistance in adult T-cell leukemia (ATL) cell lines. SO4, ST1 and KK1 are Fas-sensitive ATL cell lines, and produce small amounts of HTLV-I in vitro. Although their subclones RSO4 and RST1 are completely Fas-resistant, they produced an equivalent amount of HTLV-I to SO4 and ST1. Moreover, FAP-1 mRNA was not detected in these cell lines irrespective of Fas sensitivity. Thus, Fas resistance in ATL cells was not directly associated with the increased production of HTLV-I or FAP-1.

[Monoclonal analysis in B-cell neoplasms by the semi-nested polymerase chain reaction using consensus primers]

Monoclonality on B-cells is well known to be determined on the basis of presence of a rearranged-IgH gene, which is detected by Southern blot hybridization (SBH) remaining to be elucidated in respects of not only time-consumed, labour and cost benefit and also the use of much DNA samples. Alternative to this SBH, we examined the clinical usefulness of monoclonal analysis by the polymerase chain reaction technique which amplifies rearranged-CDR III region of IgH gene (IgH-PCR). The detective sensitivity of the IgH-PCR was different dependently upon each analysis for amplified products, namely 10(-2) per mononuclear cells in agarose gel analysis and 10(-3) in polyacrylamide gel and single strand conformation polymorphism analysis (PAGE and SSCP). Then, using the IgH-PCR and PAGE/SSCP analysis, 75 Japanese patients with B-neoplasm and 23 with T-cell neoplasms were examined for clonal IgH rearrangements. The diagnostic sensitivity in each group of B-ALL, B-CLL, B-lymphoma, HCL, AML with B-cell antigens, and non-T cell neoplasms was 88%, 92.3%, 71.4%, 100%, 57.1%, and 0%, respectively, with an overall sensitivity and specificity of 88% and 100%. This indicates that PCR analysis is very useful in detecting the clonal rearrangement of IgH genes on B-cell neoplasms, especially on ALL and CLL corresponding to neoplasms counterparting to naive B-cells.

[A case of a sudden death from Vibrio vulnificus septicemia in a patient with liver cirrhosis]

A 46-year-old male patient with alcoholic cirrhosis of the liver was carried to our out-patient clinic as he had developed shock while under routine follow-up, and died on the way to the hospital. He had been admitted several times since the diagnosis eight years ago, and was finally discharged from the hospital six weeks ago with improved physical condition and laboratory findings. A vesicle and bulla formation with phlegmon on the skin of right leg and sole of foot was noticed. Vibrio vulnificus was detected from the purulent discharge of the skin on culture. We conclude that the patient developed V. vulnificus-septicemia which resulted in sudden death. Since V. vulnificus infection may frequently take a fulminant course in patients with liver cirrhosis, adequate measures should be taken for early diagnosis and treatment to prevent the fatal outcome.

Pathological roles of interleukin-15 in adult T-cell leukemia

Interleukin-15 (IL-15) is a 14-kDa glycoprotein belonging to the same four helix bundle-cytokine family as IL-2. Although the biological activity of IL-15 in vitro has been studied extensively, its physiological role is still obscure. The receptors for IL-15 and IL-2 consist of three subunits, an unique alpha chain and shared beta and gamma chains. Since beta and gamma chains transduce the signals from the receptors, both cytokines share similar biologic functions, although IL-15 and IL-2 do not have sequence homology. The alpha chains function to increase binding affinity for each cytokines. Adult T-cell leukemia (ATL) cells constitutively express the IL-2 receptor (IL-2R) alpha and expression is believed to be essential in the early stages of disease development. We have recently shown that ATL cells also express the complete form of IL-15R including the alpha chain, and that ATL cells proliferate in response to exogenous IL-15. Since the mRNA of IL-15 is ubiquitous and is detected in many tissues and cells, it is possible that IL-15R stimulation is involved in the development and progression of ATL. Here, we review recent studies on IL-15 and IL-15R and their association with ATL and other lymphoproliferative disorders.

Adult T-cell leukemia cells over-express the multidrug-resistance-protein (MRP) and lung-resistance-protein (LRP) genes

Adult T-cell leukemia (ATL) is a T-cell malignancy caused by human T-cell-leukemia-virus-I (HTLV-I) infection. ATL comprises 4 clinical forms: acute, chronic, smoldering and lymphoma types. ATL is usually resistant to conventional chemotherapy and has a relatively poor prognosis; however, the resistance mechanisms remain undetermined. To explore the multidrug-resistance (MDR) mechanisms of ATL, we examined the expression and functional activity of MDR-related genes in peripheral-blood mononuclear cells (PBMC) from ATL patients by semi-quantitative RT-PCR and FACScan with calcein-AM. PBMC from ATL patients expressed similar or higher levels of MRP, LRP and cMOAT mRNAs, as compared with normal PBMC. In normal controls and ATL patients, MDR1 mRNA expression was undetectable in this study. PBMC from acute and chronic ATL patients expressed significantly higher levels of MRP and LRP mRNA than did normal PBMC (p < 0.01 and p < 0.05 respectively). In chronic ATL, positive correlations were apparent between levels of MRP and LRP mRNA expression (r = 0.759, p = 0.018), and between each mRNA level and the absolute number of abnormal lymphocytes in peripheral blood. Probenecid, an inhibitor of the MRP pump, significantly increased the accumulation of calcein in PBMC from 3 chronic ATL patients. Our findings suggest that the MRP and LRP genes in ATL are often activated by HTLV-I infection and may confer MDR of ATL cells in vivo. Combined chemotherapy with inhibitors of these MDR genes may be promising in the treatment of ATL.

Adult T-cell leukemia cells over-express the multidrug-resistance-protein (MRP) and lung-resistance-protein (LRP) genes

Adult T-cell leukemia (ATL) is a T-cell malignancy caused by human T-cell-leukemia-virus-I (HTLV-I) infection. ATL comprises 4 clinical forms: acute, chronic, smoldering and lymphoma types. ATL is usually resistant to conventional chemotherapy and has a relatively poor prognosis; however, the resistance mechanisms remain undetermined. To explore the multidrug-resistance (MDR) mechanisms of ATL, we examined the expression and functional activity of MDR-related genes in peripheral-blood mononuclear cells (PBMC) from ATL patients by semi-quantitative RT-PCR and FACScan with calcein-AM. PBMC from ATL patients expressed similar or higher levels of MRP, LRP and cMOAT mRNAs, as compared with normal PBMC. In normal controls and ATL patients, MDR1 mRNA expression was undetectable in this study. PBMC from acute and chronic ATL patients expressed significantly higher levels of MRP and LRP mRNA than did normal PBMC (p < 0.01 and p < 0.05 respectively). In chronic ATL, positive correlations were apparent between levels of MRP and LRP mRNA expression (r = 0.759, p = 0.018), and between each mRNA level and the absolute number of abnormal lymphocytes in peripheral blood. Probenecid, an inhibitor of the MRP pump, significantly increased the accumulation of calcein in PBMC from 3 chronic ATL patients. Our findings suggest that the MRP and LRP genes in ATL are often activated by HTLV-I infection and may confer MDR of ATL cells in vivo. Combined chemotherapy with inhibitors of these MDR genes may be promising in the treatment of ATL.

Clonal analysis of B-cell leukemias and lymphomas using the polymerase chain reaction for the third complementarity determining region of the IgH gene: a study of 75 cases from Nagasaki Japan

Using semi-nested polymerase chain reaction (PCR), we examined 75 Japanese cases of hematologic malignancies with B-cell antigens including 25 common acute lymphoblastic leukemia (ALL), 13 chronic lymphocytic leukemia (CLL), 28 B-cell malignant lymphoma (B-ML), 2 hairy cell leukemia (HCL), 7 acute myelogenous leukemia with B-cell antigens (AML-B), and 23 controls. When amplified products were analysed by a standard polyacrylamide gel electrophoresis, the sensitivity for detection of clonal IgH rearrangements in each group of ALL, CLL, B-ML, HCL, and AML-B was 88%, 92.3%, 71.4%, 100%, and 57.1%, respectively, with an overall sensitivity of 80.0%. There were no false positive results in any of the control samples. Single strand conformation polymorphism (SSCP) analysis of the amplified products gave rise to a much greater sensitivity, up to 84% overall. The false negative samples were mainly encountered in B-ML with SmIgG and non-Ig, suggesting miss-annealing between the primers used and the template DNA because of somatic hypermutation of IgH genes in such clones. This indicates that PCR analysis is very useful in detecting the clonal IgH rearrangements in B-cell malignancies, especially in ALL and CLL, but not in B-ML corresponding to neoplasms originating from pre-germinal center naive B-cells.